BEST Claw #BESTRobotics2025

Prusa Research 3D Printing National Challenge Entry #BESTRobotics2025

School: Arrowhead Park Early College High School

Team: Arrowhead Park Early College

Team #: 0553

Hub: New Mexico BEST (NM), out of New Mexico State University

Model Description

Function

            The function of this 3D Model is to grab the Golden Factoid located in the central Library of Content (LOC) on the game field. It works by being attached to two modularly-capable arms attached to a main arm, which is pulled by one of the provided small motors. Grip tape, which is to be applied to the concave portion of the model, helps to hold the desired factoids. The dimensions are built to the outer diameter of the factoids to allow for better holding potential. Two small holes, which are threaded, located on the extrusion after the first tangent plane (visible in the source file), allow for easy attachment of screws to mount the claw to the robot.

Benefits in Relation to the BEST Robot

            This model benefits the robot greatly. Without this claw, the robot would have no scoring mechanism and would be functionally useless. Additionally, the light-weight propensity of 3D printed materials allows the addition of this piece to not greatly encroach on the physical weight constraint (24 lbs.). The accuracy of additive manufacturing technology also allows for precision-fit custom parts, which increase the gripping ability of the claw without the addition of grip tape or other permitted adhesive-functioning materials.

Design Process

            Figures 6 and 7 best depict the design process pictorially. It can be seen in Figure 7 that, originally, the diameter of the claw completed a circle set to the outer diameter of the small, golf ball-shaped, factoids. This was changed to align with a previous decision matrix that said the team would focus on the LOC factoids as the overall game strategy. The outer diameter of the claw remained the same. For testing, the 3D prints were manually used (due to the servos not working), to grab a near identical PVC pipe with a 3.5” diameter but a greater height compared to that of the Golden Factoid. After this initial testing, 6 holes were added to the model to decrease the weight of the custom piece. The extrusion with the previously mentioned holes, with the first tangent plane, was also cut into the concave shape to allow for the claw to be attached. The next revision had the previously mentioned extrusion angled differently so that it could be properly attached, so that the second of this custom part could meet it correctly. 6 more holes were later added for further weight reduction and to allow strings to be attached to hold the up. These strings were later removed as they had no effect and the robot and were not visually appealing. The model was then printed in red and blue for aesthetic purposes. Finally, the part was then attached to the robot for competition. 

           In competition, despite unrelated technical issues in the first matches, the claws were capable of performing their intended task. The robot excelled in other areas though; this was due to some height-based miscalculations made when attaching the main arm to the sliding tower.  It was attached above the height recommended by one of the team members who measured it during the practice day, that height collected being capable of reaching the middle and upper level of the library if content: this made it incapable of reaching factoids in the middle level and only the upper level, which, as it is stated in the rule, must be grabbed and scored before the golden factoid. As stated before, the robot was capable of scoring points without grabbing the factoids, as drivers were able to open team gates and press the plungers for tweeter towers, which administered points when activated. The team made it into the Wildcard round for their notebook, where similar performance could be observed. The team did not qualify to progress further in the competition, but multiple learning moments were obtained, relating to mechanical and constructive applications, as well as the importance of systems thinking and time management in an engineering project.

3D Print Settings

         This piece was printed using a MakerBot Replicator+. The 3D print is printed from Polylactic Acid (PLA). The infill density is set to 10%. Basic supports are turned activated and set to 7% support density. They can be seen in Figure 8. The 3D model is printed in the orientation identical to Figure 4. Printer settings as described here, can also be observed in Figure 17, which is set within the native Fusion format.